In recent years, facilities using thermal energy which is obtained by condensing sunlight, as environmentally-friendly clean energy, have been developed actively.
As an example of such facilities, there is a solar thermal power generation facility described in, for example, PTL 1 below. The solar thermal power generation facility is provided with a compressor which compresses air as a working medium, thereby producing compressed air, a heat receiver which receives sunlight, thereby heating the compressed air, a collector (a heliostat) which irradiates the sunlight to the heat receiver, a turbine which is driven by the compressed air heated in the heat receiver, and a power generator which generates electricity by the driving of the turbine.
The solar thermal power generation facility is further provided with turbine bypass piping which is branched from heated air piping that sends the compressed air heated in the heat receiver to the turbine and connected to a chimney, and a turbine bypass valve which adjusts the flow rate of the compressed air flowing through the turbine bypass piping.
In the solar thermal power generation facility, turbine output is adjusted by a change in the number of collectors which irradiate the sunlight to the heat receiver and a change in a valve opening degree of the turbine bypass valve.
Incidentally, as a gas turbine power generation facility, a configuration is common which is provided with a compressor which compresses air, a combustor which mixes fuel into the compressed air from the compressor and burns the mixture, thereby producing combustion gas, a turbine which is driven by the combustion gas, and a power generator which generates electricity by the driving of the turbine. In the gas turbine power generation facility, at the time of start-up, a rotor rotational speed of the turbine is increased by driving an electric motor, for example. At this time, the rotational torque of the turbine rotor is controlled by adjusting the flow rate of the fuel which is supplied to the combustor.